Colinear facilitation promotes reliability of single-cell responses in cat striate cortex

Behavior is controlled by neural activity in the brain. The final outcome of this neural control may critically depend on the firing reliability of individual neurons. A nearly constant, proportional relationship is usually found between the response mean and response variance. Here we asked whether lateral interactions within striate cortex that modulate response magnitude also proportionately modify the response variance of cortical neurons. In many cases, response variability depended on stimulus organization: discrete flankers colinearly placed well outside the neuron's receptive field increased response magnitude without a proportional increase in variance, thus improving the neuron's response reliability. Since colinear flanker facilitation is often seen near the neuron's firing threshold, increased response reliability for weak stimuli may contribute to enhancing perceptual saliency.